Frequency Shift Enhancement Research Articles

Erratum: High-precision determination of the frequency-shift enhancement factor in Rb−Xe129 [Phys. Rev. A 100 , 053415 (2019)

Erratum: High-precision determination of the frequency-shift enhancement factor in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Rb</mml:mi><mml:mtext>−</mml:mtext><mml:mmultiscripts><mml:mi>Xe</mml:mi><mml:mprescripts /><mml:none /><mml:mn>129</mml:mn></mml:mmultiscripts></mml:mrow></mml:math> [Phys. Rev. A <b>100</b> , 053415 (2019)

Internal Resonance Phenomena in Coupled Ductile Cantilevers With Triple Frequency Ratio-Part II: A Mass Sensitivity Amplification Schemes

This paper, the second of two companion papers, reports a mass sensitivity amplification scheme, via amplitude and frequency shift enhancement of internal resonance (IR) in coupled ductile cantilevers with frequency ratio of three to one. The amplitude enhancement of super-harmonic resonance of order three in short cantilever can be achieved by the coupling of long cantilever via coupling overhang through the internal resonance between the low frequency mode and the high frequency mode. Such kind of enhancement mechanism is clarified by both experimental verification and numerical analysis. While the frequency shift enhancement of coupled cantilevers are experimentally demonstrated by comparatively analyzing the frequency shifts of single-cantilevers and coupled cantilevers with varying mass perturbations. The impact of coupling strength on frequency shifts of coupled cantilevers is also studied. The proposed scheme with coupled IR ductile cantilevers, can accomplish “sensing and detecting separation,” “amplitude and frequency shift enhancement,” and the linearity improvement of mass detecting, which is expected to be applicable to ultimate sensing of mass, force, field, and any other external perturbations, even under an atmospheric environments.

Cascaded rotational Doppler effect.

We propose and substantiate experimentally the cascaded rotational Doppler effect for interactions of spinning objects with light carrying spin angular momentum. Based on mirror symmetry for electromagnetic interactions, we reveal that the frequency shift can be doubled through cascading two rotational Doppler processes that are mirror-imaged to each other. This effect is further experimentally verified with a rotating half-wave plate, and the mirror-imaging process is achieved by reflecting the frequency-shifted circularly polarized wave upon a mirror with a quarter-wave plate in front of it. The mirror-symmetry-protected frequency shift enhancement could be applied for detection of rotating systems ranging from molecules to macroscopic bodies with high precision and sensitivity.

Collision-induced spin exchange of alkali-metal atoms with 3He

Collisions of atoms and molecules in external electromagnetic fields can depolarize electronic and nuclear spins, leading to decoherence of quantum superposition states. The fundamental microscopic processes giving rise to spin depolarization are spin exchange and spin relaxation. In this work, we present an analysis of spin exchange transitions in collision of alkali metal atoms with 3He. We use accurate ab initio calculations to evaluate the electron spin density of Li-He and the interaction energy of Rb-He. The Fermi contact interaction constants for the complexes of Na, K, and Rb atoms with 3He are extracted from the measured frequency shift enhancement factors using the ab initio interaction potentials. The spin density calculations also yield the hyperfine pressure shift of Li-He.

Thermal frequency drift suppression in tunable DFB lasers by plasma induced frequency shift enhancement

The authors propose enhanced-plasma-effect (EPE) lasers for coherent optical frequency division multiplexed networks. In the EPE lasers, the blue frequency shift due to the plasma effect is enhanced by incorporating a very thick p-side optical guide layer as a carrier reservoir for multiple quantum-well distributed feedback laser and it surpasses the red frequency shift due to the thermal effect. The results of demonstrating a frequency step response maintained in the blue shift region and an enhanced blue shift frequency modulation response over the whole modulation frequency range from DC are presented for the first time. >